Snap locking device for a container with a cover

ABSTRACT

A snap locking device for a container with a cover which is lockable to the container via a bistable loosening flange. The flange is provided on the cover or the container and is adapted to cooperate with a locking edge on the container or the cover, respectively. The bistable loosening lines, and its portions disposded between at least two weakened lines are exteriorly provided with wall reinforcements which extend axially over the bistable loosening flange. The wall reinforcements preferably extend axially over the stationary cover flange disposed in extension of the loosening flange.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The invention concerns a snap locking device for a container with acover, said cover being lockable to the container via a flange which isformed on the cover or the container and which may be caused to assume aloosened and a locked position, respectively, and is adapted tocooperate with a locking edge on the container or the cover, theloosening flange, which is thus bistable, being formed withsubstantially vertical weakened lines.

2. Discussion of the Art:

Containers of such a type are known e.g. from the French PatentApplication No. 2 377 333 which concerns the principle of lockingdevices comprising bistable components. However, such a simple closingarrangement for packages above a certain size is not sufficient when apackage is to be used for storing both high-viscous and low-viscoussubstances. These may be e.g. food products, such as butter, margarine,or jam, and paint, or they may be substances for use in the medical andpharmaceutical industries.

The Danish Published Application No. 145 194 describes a container/coverstructure which operates with a bistable locking flange. However, thisis a structure which has been found not to be stable in transport,storage and stacking. Further, the package is not provided with a sealdevice, which is increasingly demanded by many buyers.

The Danish Patent Application No. 3870/83 concerns a package which isformed with seal, but constructed in such a manner as to operate uponrupture of vertical wall constrictions; however, it has been found thatthis form of seal has a poor control function because the wallconstrictions have very little information value. The information valueof the seal state is particularly essential in the pharmaceuticalindustries, and in the other fields of use there is a tendency for morestringent demands on the opening and closing mechanism of packages.

SUMMARY OF THE INVENTION

The object of the invention is to provide a container structure whichprovides a hermetically tight package in an unloaded state and also whensubjected to impact or pressure, and which moreover has the property ina situation of use that the cover can temporarily be protected againstimpacts from the surroundings and the contents.

This object is achieved by constructing a snap locking cover devicewhich in addition to providing a hermetically tight package, thiscontainer structure also has the advantage that the pair of weakenedlines, serving as a seal device for locking the cover to the container,is provided so that the flange portion disposed between them is integralwith the stationary flange portion, so that the resulting, relativelyrigid edge face serves as snap locking means in which the flange may bepivoted to snap the cover onto the container. When provided with anincreased radial wall thickness said flange portion will have anincreased rigidity so that the snap locking effect is improved. Thissnap locking device is used in connection with temporary closure of thecontainer, which is thus kept tight in case of shock impacts andpossible overturning.

Further, when the snap locking means on the cover is formed with radialwall reinforcements and incorporates an additional seal means, thevisual impression of the container as a so-called pilfer-proof structureis improved.

In a preferred embodiment, the cover is provided with two snap lockingdevices so that two pairs of weakened lines are present, each of whichextends over a relatively small part of the circumference of the coverand is disposed diametrically opposite each other. This entails thateach of the cover circumference parts disposed between the snap lockingdevices extends through a circular arc of below 180°, and thisdiscontinuity of the circumference causes the ring tension of the coverto be reduced, which contributes to easy upward and downward movement ofthe locking flange; moreover, opening of the container according to theinvention will not result in part of the contents being ejected becauseof the superpressure which is otherwise often caused upon opening ofknown containers. The embodiment of the cover having two snap lockingdevices is additionally ideal in the sense that two such devices (andthus two snap locks) are sufficient to ensure a pilfer evident cover, sothat an attempt at unauthorized penetration into the container at thelocking flange over an edge arc length of below 180° is impossible,without breaking one of the seals formed by the snap locking devices.

Further, the idea of the snap locking device of the invention is alsothat the loosening flange bistable in that it is stable in two separatepositions and may be selectively provided on either the container or thecover, so that a radially protruding locking edge for engagement withsaid flange is correspondingly provided on the cover or the container.

As an additional closure/sealing promoting feature, the engagement facesof the container and the cover may be made conical, the conicity of thecover faces being slightly smaller than that of the container faces.This, in combination with the snap locking device of the invention, isto contribute to improved sealing at the temperary closure of thecontainer when, in a given situation of use, the materials are to bedispensed repeatedly. In this arrangement, the cover is biased to somedegree before the snap locking effect is established, which is thus tomake the snap locking additionally effective when the bistable lockingflanges are in a folded-up state.

In an embodiment where the bistable loosening flange is provided for thecontainer, it will be appreciated that the opposite proportion betweenthe conicities of the container and the cover faces is to be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained more fully by the following descriptionof a preferred embodiment with reference to the drawings, in which

FIG. 1 is an axial sectional view illustrating the snap locking deviceof the container/cover structure with the loosening flange of the coverin a folded-up state,

FIG. 2 is an axial sectional view of the container/cover structure withthe loosening flange of the cover in its locking state,

FIG. 3 is a top view of the container cover in a locked state, and

FIG. 4 illustrates the container/cover structure in a partiallyperspective view showing the loosening flange of the cover in itsfolded-up state.

DETAILED DESCRIPTION OF THE DRAWINGS

It appears from FIG. 1 that the cover 2 is formed with a substantiallyplanar cover face 16 merging into a sealing face 9, which is upwardlyhollow in cross-section and which is adapted to receive the edge faces10 of the container, said faces 9 and 10 thus forming the primary snaplocking sealing device of the structure. The cover face is moreoverconnected with a stationary cover flange 6 and has also a sealing edge 8in its direct, axially downwardly directed extension, said sealing edge8 and the cover flange 6 defining an annular, upwardly hollow groove 17.This groove is adapted to partly receive a so-called guide rib 7, whichprojects upwardly from a radially outwardly protruding locking edge 5,which is connected with the container wall 1 somewhat below thecontainer edge 10.

It will be seen from FIG. 1 that the upper engagement edge 10 of thecontainer 1 is adapted to cooperate with the interior faces 9 of thecover 2 over a relatively long extent. This is because the cover whenbeing applied slides down over the container edge, so that this edge isautomatically cleaned of any container contents disposed thereon, andthis cover type has thus a certain mechanical self-cleaning effect viathe snap lock.

It is additionally illustrated how the stationary cover flange 6 isconnected, via a wall constriction 4, with an extension, radial inlocking position, which thus constitutes a so-called bistable looseningflange 3, which is stable in two positions and is pivotable about wallconstriction 4, which is shown in its folded-up, non-locking position.

The container cover is formed with wall reinforcements 11 in the form ofradial thickenings preferably at two diametrically opposite points, sothat the cover edge at these arc sections each constitutes so-calledsnap locking means (indicated by the unit 12 and comprising the elements3', 4, 6 and 11 as well as 14 and 15), the length of these arc sectionseach being defined by two weakened lines 13, which are shown best inFIG. 3. When the container is to be closed, the cover is placed with itstwo flanges 3 in their folded-up state on the container, so that thecover assumes a position by its own weight, where the sliding face 14 ofthe flange 3' rests on the locking edge 5. Axial pressure impact willcause the cover to be moved further down, so that the sliding face 14 isforced radially outwardly until the boss projection 15 of the flange 3'is passed, and then the snap locking effect occurs (see also FIG. 4).The provision of the wall reinforcements 11 imparts improved radialrigidity to the snap locking devices, and this rigidity is precisely tocontribute to effective, temporary closing and sealing of the cover whenits bistable flange 3 is present in the folded-up state.

With respect to FIGS. 1 and 2 it is readily evident that the structuredescribed above can be modified so that the bistable locking flange isprovided on the upper edge portion of the container part. Then, thestationary portions 5, 7 and 10 constitute the cover function of thecontainer 1, the bistable and snap-locking function of the cover 2 beingtransferred to the container. This selection of the position of thebistable cover flange may have importance in connection with variouscustomers' aesthetic requirements, packaging technique, storagestability, selection of handling mode and preferred allocation of theopening forces and the like.

To make the snap lock function additionally effective, the cooperatingfaces of the groove 17 and the guide rib 7 may be formed with mutuallydifferent conicities, the greatest being that of the guide rib. Thiscauses the cover to be biased to some extent before locking, and thisbias has moreover a sealing function. The axial rigidity has theadditional effect that the cover, when being removed, has a certain"self-loosening" effect, thus ensuring easy removal of the cover inspite of the relatively strongly dimensioned snap locking device.

The above-mentioned conicity between the guide rib 7 and the groove 17might conceivably also be provided on the engagement faces 9 and 10 ofthe container and the cover.

I claim:
 1. A snap locking device for a container with a cover, saidcover being lockable to the container, said device comprising a flangewhich is formed on the cover, said flange being movable between aloosened and a locked position and is adapted to cooperate with alocking edge on the container, said flange, which is thus bistable,being formed with substantially vertical weakened lines, wherein saidflange portions disposed between at least two weakened lines areexteriorly provided with wall reinforcements, said wall reinforcementsextending axially over the bistable flange and over a stationary coverflange disposed in extension of said flange.
 2. A snap locking deviceaccording to claim 1, wherein two pairs of weakened lines are provided,said pairs being disposed diametrically opposite each other.
 3. A snaplocking device according to claims 1 or 2, wherein the bistable flangeis provided on the cover in extension of the stationary cover flange andis adapted to engage a radially outwardly protruding locking edge on thecontainer.
 4. A snap locking device according to claim 3, wherein thecontainer and cover have substantially vertically oriented engagementfaces which are conical, and further wherein the faces of the cover havea slightly smaller conicity than the engagement faces of the container.